全文获取类型
收费全文 | 2024篇 |
免费 | 128篇 |
国内免费 | 90篇 |
专业分类
林业 | 211篇 |
农学 | 92篇 |
基础科学 | 72篇 |
125篇 | |
综合类 | 596篇 |
农作物 | 182篇 |
水产渔业 | 28篇 |
畜牧兽医 | 881篇 |
园艺 | 34篇 |
植物保护 | 21篇 |
出版年
2024年 | 12篇 |
2023年 | 28篇 |
2022年 | 89篇 |
2021年 | 112篇 |
2020年 | 90篇 |
2019年 | 132篇 |
2018年 | 68篇 |
2017年 | 98篇 |
2016年 | 79篇 |
2015年 | 76篇 |
2014年 | 100篇 |
2013年 | 95篇 |
2012年 | 125篇 |
2011年 | 136篇 |
2010年 | 113篇 |
2009年 | 127篇 |
2008年 | 119篇 |
2007年 | 110篇 |
2006年 | 92篇 |
2005年 | 64篇 |
2004年 | 54篇 |
2003年 | 26篇 |
2002年 | 38篇 |
2001年 | 46篇 |
2000年 | 37篇 |
1999年 | 28篇 |
1998年 | 19篇 |
1997年 | 19篇 |
1996年 | 11篇 |
1995年 | 21篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 18篇 |
1991年 | 8篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有2242条查询结果,搜索用时 15 毫秒
21.
Effects of apple pomace proportion levels on the fermentation quality of total mixed ration silage and its digestibility,preference and ruminal fermentation in beef cows
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jiachen Fang Yang Cao Masatoshi Matsuzaki Hiroyuki Suzuki 《Animal Science Journal》2016,87(2):217-223
Four Japanese black beef cows were used in a 4 × 4 Latin square to evaluate the fermentation quality, digestibility, ruminal fermentation and preference of total mixed ration (TMR) silages prepared with differing proportions of apple pomace (AP). Experimental treatments were the control (no AP added, CAP), 5% (low, LAP), 10% (medium, MAP) and 20% (high, HAP) of TMR dry matter (DM) as AP. All TMR silages were well preserved. Ethanol was produced in silages containing AP and the amount increased with the proportion of AP (P < 0.05). Nutrient digestibility with LAP, MAP and HAP treatment was lower than that with CAP treatment (P < 0.05). The ruminal molar proportion of acetic acid increased (P < 0.05), but the ruminal ammonia‐N concentration decreased (P < 0.05) as the proportion of AP increased. The preference of the animals was highest for HAP, followed by MAP, CAP and LAP. This study demonstrates that decrease in nutrient digestibility might be related to the ethanol produced naturally from AP. Therefore, the proportion of AP in TMR silages should be less than 5% of dietary DM. 相似文献
22.
The aim of this study was to evaluate the chemical composition, energy and amino acid profile of dried salmon silage (DSS) for broilers. The DSS was obtained by acid digestion of salmon mortalities and subsequently co‐dried with wheat bran in a 70:30 ratio (70 parts silage and 30 parts wheat bran). Samples of DSS were evaluated for chemical composition, gross energy, nitrogen‐corrected true metabolizable energy (TMEn), mineral content, total and digestible amino acids for broilers, and amino acid score. The chemical composition of DSS was (mean ± SD): moisture (12.3 ± 0.8%), crude protein (44.0 ± 1.1%), ether extract (5.0 ± 2.4%), crude fiber (3.3 ± 0.4%) and ash (9.4 ± 0.6%). The gross energy and TMEn for broilers were 4 069 kcal/kg and 2 613 kcal/kg, respectively. The DSS mineral composition showed a high content of calcium (1.01%) and phosphorus (1.08%). The DSS had high levels of digestible methionine (0.74%), lysine (2.27%), and threonine (1.16%), and did not present limiting amino acids for broilers. Nutritional composition of DSS showed high protein content with an amino acid profile considered to be suitable as a protein source for broiler feeding. 相似文献
23.
Effects of apple pomace‐mixed silage on growth performance and meat quality in finishing pigs
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jiachen Fang Yang Cao Masatoshi Matsuzaki Hiroyuki Suzuki Hirofumi Kimura 《Animal Science Journal》2016,87(12):1516-1521
We measured the growth performance and meat quality of 10 crossbred (Yorkshire × Duroc × Landrace) neutered male pigs to evaluate the effects of apple pomace‐mixed silage (APMS). The pigs were divided into two groups and were respectively fed the control feed and the AMPS ad libitum during the experiment. No difference was found in the finished body weight, average daily gain, carcass weight, back fat thickness or dressing ratio between the control and the AMPS treatments, but average dairy feed intake (dry matter) was significantly lower and feed efficiency was significantly higher using the APMS treatment (P < 0.05). With regard to meat quality, the APMS increased the moisture content but decreased the water holding capacity (P < 0.05) compared with the control treatment. Furthermore, the APMS affected the fatty acid composition of the back fat by increasing linoleic acid (C18:2n6), linolenic acid (C18:3) and arachidic acid (C20:0) levels, while decreasing palmitic acid (C16:0), palmitoleic acid (C16:1) and heptadecenoic acid (C17:1) levels, compared with the control treatment. These results indicate that feeding fermented apple pomace to finishing pigs increases the feed efficiency and affects the meat quality and fatty acid composition of back fat. 相似文献
24.
Strains TH 14, TH 21 and TH 64 were isolated from tropical silages, namely corn stover, sugar cane top and rice straw, respectively, prepared in Thailand. These strains were selected by low pH growth range and high lactic acid‐producing ability, similar to some commercial inoculants. Based on the analysis of 16S ribosomal RNA gene sequence and DNA‐DNA relatedness, strain TH 14 was identified as Lactobacillus casei, and strains TH 21 and TH 64 were identified as L. plantarum. Strains TH 14, TH 21, TH 64 and two commercial inoculants, CH (L. plantarum) and SN (L. rhamnosus), were used as additives to fresh and wilted purple Guinea and sorghum silages prepared using a small‐scale fermentation method. The number of epiphytic lactic acid bacteria (LAB) in the forages before ensilage was relatively low but the numbers of coliform and aerobic bacteria were higher. Sorghum silages at 30 days of fermentation were all well preserved with low pH (3.56) and high lactic acid production (72.86 g/kg dry matter). Purple Guinea silage inoculated with LAB exhibited reduced count levels of aerobic and coliform bacteria, lower pH, butyric acid and ammonia nitrogen and increased lactic acid concentration, compared with the control. Strain TH 14 more effectively improved lactic acid production compared with inoculants and other strains. © 2016 Japanese Society of Animal Science 相似文献
25.
"民工"从语词上界定可以理解为:农民和工人双重身份,本文放在传统农业向现代农业转变的大背景下,着重考察了游离在城乡之间的农民工主题身份的认定,及其未来的阶级、阶层走向,按照断裂社会的运作逻辑,经过分化重组的当下社会必定会出现新的阶级、阶层.这些阶级、阶层与传统阶级、阶层有什么区别和联系,农民工如果被假定为工人阶级而客观存在.那么这些生活在城市里农民能否获得市民身份的认同?对这些问题的回答有利于我们走出"城乡二元格局"的困境,有利于构建更加稳定、和谐的社会主义新农村. 相似文献
26.
Growth and carbon dynamics in mixed grass–red clover leys were simulated using a growth model for pure stands based on radiation use, allocation within plant and loss of biomass. The model and its parameter values were taken from previous applications of the model to pure swards of grass and red clover grown in the same experiment at the same sites and years. 相似文献
27.
以陕西省关中平原为研究区域,应用点扩散函数、混合像素面积权重法和中值像素变异权重法将基于Landsat卫星遥感数据反演的分辨率为30 m的条件植被温度指数(VTCI)干旱监测结果上推至930 m的干旱监测结果,并与Aqua MODIS数据反演的分辨率为930 m的VTCI干旱监测结果进行对比分析,以期为两种空间尺度的干旱监测结果的综合应用提供技术支持。以MODIS数据反演的VTCI为参考,应用相关系数、均方根误差、半变异函数的估计值和图像纹理特征等对尺度上推的VTCI进行评价。结果表明,点扩散函数和混合像素面积权重法的尺度上推效果均较好,而中值像素变异权重法的尺度上推效果较差,说明点扩散函数和混合像素面积权重法均适用于研究区域VTCI干旱监测结果的尺度转换,且点扩散函数的数据处理过程更为简单。典型样点VTCI的尺度上推结果表明,空间异质性越小,尺度上推的结果越好。 相似文献
28.
青贮玉米收获机是青贮玉米饲料机械化生产中重要的农业装备之一。为此,分析了黑龙江省青贮玉米收获机械的现状和发展趋势;指出了青贮玉米收获机械发展中存在的问题;提出了相应的解决对策。其目的是为进一步加快黑龙江省青贮玉米收获机械的发展献计献策。 相似文献
29.
根据热力学第一定律,利用集中参数法,导出了混合状态下散体非稳态传热方程:T-T0T∞-T0=1-e-τ上述理论与实验结果相当吻合,是研究散体传热理论问题的重要参考 相似文献
30.
为探究辣椒单株结果数的遗传机制,以单株结果数差异较大的辣椒材料XHB(P1)和B14-01(P2)为亲本,构建四世代遗传家系即P1、P2、F1、F2。运用主基因+多基因多世代联合分析法,研究辣椒单株结果数的遗传规律。结果表明:辣椒单株结果数符合2对加性-显性-上位性主基因模型(2MG-ADI)。2对主基因的加性效应值da、db分别为-16.33、-13.05,2对主基因的显性效应值ha、hb分别为-10.02、-2.51。2对主基因间的加性×显性(jab)互作效应和显性×加性(jba)互作效应的效应值分别为8.69和12.93,加性×加性上位性(i)互作效应值为6.86,显性×显性(l)的互作效应值为7.23,主基因间的效应以加性效应为主,其次是加性×显性上位性互作效应。主基因遗传率为68.10%,环境引起的变异占比31.9%... 相似文献